1. Field
One embodiment of the present invention relates to a discrete track type magnetic recording medium, a method for manufacturing the same, and a magnetic recording apparatus.
2. Description of the Related Art
A recently frequent problem with magnetic recording media incorporated into hard disk drives (HDD) is that the interference between adjacent tracks prevents track density from being improved. In particular, how to reduce write bleeding resulting from a fringe effect exerted by magnetic fields from a magnetic head is an important technical problem.
To solve this problem, a proposal has been made of a discrete track magnetic recording medium (DTR medium) having a magnetic recording layer processed so as to physically separate recording tracks from one another. The DTR medium enables the inhibition of a side erase phenomenon in which information in an adjacent track is erased during write operation and a side read phenomenon in which information in an adjacent track is read during read operation, allowing an increase in track density. Therefore, the DTR medium is expected as a magnetic recording medium that can achieve a high recording density.
In conventional DTR media, a magnetic recording layer is removed from each recess between adjacent recording tracks in a recording area down to an underlayer. An embedding layer made of a nonmagnetic material is then filled into recesses so as to flatten the surface of the medium (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2006-92659). In the DTR medium, the embedding layer filled in the recesses has a bottom portion in contact with the underlayer and sidewalls in contact with the magnetic recording layer formed into protrusions. Thus, the embedding layer is in contact with the different materials, resulting in degraded adhesion. Consequently, when the magnetic recording apparatus is driven, the embedding layer is subjected to peeling, degrading the flatness of the medium surface. Further, the magnetic head is disadvantageously likely to be damaged.
On the other hand, a magnetic recording medium is known in which a part of the magnetic recording layer is selectively etched but is left in the recesses (U.S. Pat. No. 6,999,279). However, there is a great difference in height on the surface of the magnetic recording medium. This disadvantageously degrades flying properties of a magnetic head.